CKEDITOR.plugins.add( 'cosimg', {
    icons: 'cosimg',
    init: function( editor ) {
        editor.addCommand( 'cosimg', new CKEDITOR.dialogCommand( 'cosimgDialog' ) );
        editor.ui.addButton( 'cosimg', {
            label: 'Insert Abbreviation',
            command: 'cosimg',
            toolbar: 'insert'
        });

        CKEDITOR.dialog.add( 'cosimgDialog', this.path + 'dialogs/cosimg.js' );
    }
});